I am using a G4 PowerMac, purchased last August, and recently began to use an extension for my headphones as they would not reach from the tower on the floor to my head. All went well for awhile, but now it seems like the port is not working at all - the headphones work, and the internal speakers work. From what I can gather of other posts, it is possible to wear the headphone jack out. Can this be the case? I have not plugged in and unplugged that many times. And how do I go about getting it repaired? Any thoughts are appreciated.